With input from some of my colleagues in the Canadian Society for Senior Engineers, I am responding to recent letters in the Leader-Post and a news article concerning perceived health risks of nuclear plant workers and of people living near nuclear power plants.
It is clear from the performance of Canada's nuclear power plants that there is no evidence of a higher risk of developing cancer by either nuclear plant workers or the general public. Exposure levels outside Canada's nuclear power plants are no different from naturally occurring background radiation levels, with no demonstrated adverse health effects.
The study used in the letters as so-called "evidence' of higher risks appears to be based on an old assumption, adopted some 50 years ago after studies of DNA damage in fruit flies. This is called the Linear No Threshold (LNT) assumption. This assumption extrapolates in a straight line the cancer data following high levels of radiation exposure and dose rates to low-level radiation exposures and erroneously predicts a risk of cancer from low-level exposures and dose rates, where there is no statistically valid evidence of increased cancer. The LNT assumption is incorrect. Unfortunately, while scientifically incorrect, the LNT Hypothesis is still imbedded in much regulation created following the Second World War and the advent of peaceful uses of nuclear energy. Such deeply immoral misuse of our scientific heritage to predict cancer risks has been discouraged by prominent international scientific societies. These predictions of cancer risks were never realized and are contradicted by evidence of lower risks of developing cancer.
There are an increasing number of international and Canadian scientific studies that observe beneficial health effects of low-level radiation exposures. This observed phenomenon is called radiation hormesis. The many applications of medical isotopes in diagnostic procedures and cancer treatments are day-to-day examples of how radiation has been benefitting humanity. These are well known by all levels of medical practitioners, accepted and indeed demanded by the public.
The old LNT assumption has been disproved in many scientific studies, but it is still being used by those whose professional or political reputations or ambitions depend on the propagation of this misinformation. This is not unlike when Galileo, to save his life, was forced to retract his correct observation that the Earth rotates around the Sun and not the other way around. Credibility, influence and power are strong motivators in preventing the truth or contradictions to the belief of the ruling bodies to be made public.
The anti-nuclear movement tries to instill a level of fear that is unsubstantiated by actual facts and experiences. The nuclear industry is the most intensively regulated industry in Canada in terms of environmental impact assessment and stringent performance criteria to be met during the life cycle of planning, construction, operation and eventual decommissioning of power plants. The close scrutiny by this multi-facetted regulatory process should instill a high level of confidence in the safeguarding of workers and the general public. The excellent safety performance record of Canada's CANDU reactors is a clear example of this to all Canadians.
- Van Vliet is a board member of the Canadian Society for Senior Engineers and a Regina resident.